This study poses the question of how Poland can transition to a low emissions economy as successfully as it underwent transition to a market economy in the early 1990s. With the EU policies on climate change and 2020 targets already in place, Poland faces immediate policy challenges. What are the implications for Poland of implementing EU policies on energy and climate change? Could the country commit to more ambitious overall greenhouse gas mitigation targets for the longer term—to 2030 and beyond? What technological options are available, and how expensive are they? Would there be high costs in lost growth and employment? The report addresses these questions while advancing the methodological approach of the World Bank’s low carbon studies by integrating ‘bottom-up’ engineering analysis with ‘top-down’ economywide modeling. The economic impact is presented using a unique macroeconomic version of the well-known marginal abatement cost curve.